\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\begin{document}
\small
\begin{tikzpicture}[>=latex,scale=1.3]
  \fill [pattern=north east lines] (2,-1)--(2.2,-1) to [bend left=30] (2.2,1) --(2,1) to [bend left=-30]
  (2,-1);
  \draw [thick](2,1) to [bend left=-30] (2,-1);
  \draw [dashed] (-3,0)--(4,0);
  \node at (3,0) [above]{$F$};
  \draw (3,0) [fill=black] circle (1.5pt);
  \draw (-2.5,0) rectangle (-2, .5);
  \draw (-2.25, .5) to [bend left=30] (-2.25,1) to [bend left=30]  (-2.25, .5);
  \draw [dashed](2.5,0) rectangle (2.75, .25);
  \draw [dashed](2.625, .25) to [bend left=30] (2.625, .5) to [bend left=30]  (2.625, .25);
\end{tikzpicture}
\end{document}